Transfer chamber for vacuum processing system

ABSTRACT

A transfer chamber for a substrate processing tool includes a main body having side walls adapted to couple to at least one processing chamber and at least one load lock chamber. The main body houses at least a portion of a robot adapted to transport a substrate between the processing chamber and the load lock chamber. A lid couples to and seals a top of the main body of the transfer chamber. The transfer chamber also has a domed bottom adapted to couple to and to seal a bottom portion of the main body of the transfer chamber.

[0001] The present application claims priority from U.S. ProvisionalPatent Application Serial No. 60/390,629, filed Jun. 21, 2002, andtitled “Transfer Chamber For Vacuum Processing System” and from U.S.Provisional Patent Application Serial No. 60/392,578, filed Jun. 28,2002, and titled “Transfer Chamber For Vacuum Processing System”, bothof which are hereby incorporated by reference herein in their entirety.

FIELD OF THE INVENTION

[0002] This invention is generally concerned with processing systemsused for processing substrates, and is more particularly concerned witha transfer chamber for use in such a system.

BACKGROUND OF THE INVENTION

[0003] Conventional techniques for manufacturing flat panel displays orsemiconductor devices entail applying a sequence of processes to asubstrate such as a glass plate or a silicon wafer. The processes to beapplied may include thermal processing, physical vapor deposition (PVD),chemical vapor deposition (CVD), etching, etc. Typically, each processin the sequence of processes is performed in a respective processingchamber. Accordingly, the substrates upon which the processes areperformed must be transferred from one processing chamber to another.

[0004] It is also conventional to incorporate a number of differentprocessing chambers in a single processing tool, wherein the processingchambers are coupled around the periphery of a central transfer chamber.FIG. 1 is a somewhat schematic vertical cross-sectional view of aconventional processing tool 11. The processing tool 11 includes acentrally-positioned transfer chamber 13. A load lock chamber 15 and aprocessing chamber 17 are shown coupled to respective sides of thetransfer chamber 13. One or more additional process chambers and/or loadlock chambers, which are not shown, may also be coupled to respectivesides of the transfer chamber 13. The load lock chamber 15 is providedto accommodate introduction of substrates into the processing tool 11from outside of the processing tool 11.

[0005] The transfer chamber 13 includes a main body 19 having side walls21 (of which only two are visible in FIG. 1). Each side wall 21 may beadapted to have a load lock or processing chamber coupled thereto. Thetransfer chamber 13 also includes a top 23 supported on the main body19. A lid 25 is provided to sealingly close the top 23 of the transferchamber 13.

[0006] A lower end of the transfer chamber 13 is closed by asubstantially annular bottom 27. The bottom 27 of the transfer chamber13 has a central aperture 29 which accommodates installation of asubstrate handling robot 31 in the transfer chamber 13. The substratehandling robot 31 is adapted to transfer substrates among the processingchambers 17 and the load lock chamber or chambers 15 coupled to transferchamber 13.

[0007] To minimize the possibility of contamination of substratesprocessed in the processing tool 11, it is customary to maintain avacuum in the interior of the transfer chamber 13. Hence, the processingtool 11 may be referred to as a vacuum processing system. A pumpingsystem, which is not shown, may be coupled to the transfer chamber 13 topump the transfer chamber 13 down to a suitable degree of vacuum.

[0008] Also illustrated in FIG. 1 is an actuator 33 which selectivelyopens and closes a slit valve 35 associated with the processing chamber17. When the slit valve 35 is in an open position (not shown), asubstrate may be introduced into or removed from the processing chamber17. When the slit valve 35 is in the closed position illustrated in FIG.1, the processing chamber 17 is isolated from the transfer chamber 13 sothat a fabrication process may be performed on a substrate within theprocessing chamber 17.

[0009] Processing tools, and in particular the transfer chamber portionsthereof, are manufactured in a variety of sizes. In some cases it isnecessary or desirable that the transfer chamber 13 be quite large. Forexample, in a processing tool used for fabricating flat panel displays,the glass plate substrates that are processed currently range from about0.5 to 1.5 meters per side, and may reach 2-3 meters per side in thenear future. Accordingly, a very large transfer chamber is required forsuch applications. In addition, it may be desirable to increase thenumber of processing chambers and/or load locks included in theprocessing tool, which also may require that the transfer chamber bemade large. However, increasing the size of a transfer chamber increasesvacuum induced stresses in components thereof such as the bottom of thetransfer chamber. To accommodate such stresses, the thickness of thebottom of a transfer chamber may be increased to provide increasedstrength. However, increased thickness of the transfer chamber bottomresults in greater weight, increased difficulty in manufacture, andhigher cost.

SUMMARY OF THE INVENTION

[0010] According to a first aspect of the invention, a transfer chamberis provided, including a main body having side walls adapted to coupleto at least one processing chamber and at least one load lock chamber.The main body is also adapted to house at least a portion of a robotadapted to transport a substrate between the at least one processingchamber and the at least one load lock chamber. The inventive transferchamber also includes a lid adapted to couple to and to seal a topportion of the main body of the transfer chamber. The inventive transferchamber further includes a domed bottom adapted to couple to and to seala bottom portion of the main body of the transfer chamber.

[0011] According to a second aspect of the invention, a vacuumprocessing system includes a transfer chamber as described above inconnection with the first aspect of the invention. The inventive vacuumprocessing system also includes at least one processing chamber coupledto the main body of the transfer chamber and at least one load lockchamber coupled to the main body of the transfer chamber. The inventivevacuum processing system further includes a robot that at leastpartially extends through the domed bottom into the transfer chamber.The robot is adapted to transport a substrate between the at least oneprocessing chamber and the at least one load lock chamber via thetransfer chamber.

[0012] According to a third aspect of the invention, a method of forminga domed bottom for a transfer chamber is provided. The transfer chamberis adapted to couple at least one load lock chamber to at least oneprocessing chamber. The method includes selecting a material and forminga domed bottom from the material. The domed bottom has an outer diametersized to fit against and configured to form a seal with a bottom portionof a main body of a transfer chamber. The domed bottom also has anaperture having a diameter sized to accommodate at least a portion of arobot. The robot is adapted to transfer substrates between at least oneload lock chamber and at least one processing chamber coupled to thetransfer chamber.

[0013] Because the transfer chamber bottom provided in accordance withthe invention has a domed configuration, the inventive transfer chamberbottom exhibits greater strength than would a transfer chamber bottom ofequal thickness having a flat configuration. Accordingly, the inventivetransfer chamber bottom may be made thinner than conventional flatbottoms of transfer chambers of comparable size, thereby providingsavings in cost and weight.

[0014] Further features and advantages of the present invention willbecome more fully apparent from the following detailed description ofexemplary embodiments, the appended claims and the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a vertical cross-sectional view of a conventional vacuumprocessing system;

[0016]FIG. 2 is a vertical cross-sectional view of a vacuum processingsystem provided in accordance with a first embodiment of the invention;

[0017]FIG. 3 is an exploded view of a transfer chamber that is part ofthe inventive vacuum processing system of FIG. 2;

[0018]FIG. 4 is a simplified schematic side view of an exemplaryembodiment of the transfer chamber of FIGS. 2 and 3; and

[0019]FIG. 5 is a schematic vertical cross-sectional view of a vacuumprocessing system provided in accordance with another embodiment of theinvention.

DETAILED DESCRIPTION

[0020] In accordance with the invention, the bottom of a transferchamber is provided in a domed configuration, thereby achieving greaterstrength for a given thickness of the bottom and reducing the interiorvolume of the transfer chamber. As a result, the bottom of the transferchamber may be made thinner than conventional transfer chamber bottoms,so that a savings in cost and weight is realized. The reduced interiorvolume of the transfer chamber also may decrease pump down times,thereby increasing throughput.

[0021] An embodiment of the invention will now be described withreference to FIGS. 2 and 3.

[0022]FIG. 2 is a view similar to FIG. 1 of a processing tool (vacuumprocessing system) 201 provided in accordance with an embodiment of thepresent invention. The inventive processing tool 201 includes a noveltransfer chamber 203. A conventional load lock chamber 15 (which may be,for example, a double dual slot load lock (DDSL) or other conventionalload lock) and a conventional processing chamber 17 are shown coupled tothe inventive transfer chamber 203. It will be understood that one ormore additional process chambers and/or load lock chambers may also becoupled to the transfer chamber 203, although not shown in the drawings.A substrate handling robot 205 is disposed within the transfer chamber203. As with the conventional system of FIG. 1, a pumping system (notshown) may be coupled to the inventive transfer chamber 203 to pump downthe transfer chamber 203 to a suitable degree of vacuum. Forconvenience, the inventive transfer chamber 203 will be described withreference to both FIG. 2 and FIG. 3 (which is an exploded view of theinventive transfer chamber 203).

[0023] With reference to FIGS. 2 and 3, the transfer chamber 203includes a main body 207, which may be, for example, machined from asingle piece of material such as aluminum. Other materials may beemployed. As described further below, in at least one embodiment of theinvention the height of the main body 207 (H_(mB)) is minimized so as toreduce the overall volume and weight of the transfer chamber 207. Themain body 207 may have a cylindrical interior wall 209 and an exteriorwall 211 having flat regions 213 which form side walls 215 (FIG. 2) thatare adapted to couple to processing chambers or load lock chambers. Inat least one embodiment, each side wall 215 (FIG. 2) may, for example,have a thickness of about two inches at its thinnest point (e.g., thecenter of each flat region 213). Other side wall thicknesses may beemployed. Each side wall 215 may include one or more respective slits217 (FIG. 3) through which a substrate (not shown) may be transferredfrom the transfer chamber 203 to a processing chamber 17, or vice versa,by the substrate handling robot 205. A slit valve (not shown in FIGS. 2and 3) may be associated with each slit 217 to selectively open andclose each slit 217. In the embodiment of FIGS. 2 and 3, the transferchamber 203 includes two slits 217 a, 217 b for allowing substrates tobe loaded into and out of the load lock chamber 15 at two differentheights. The slits 217 a, 217 b may be sealed, for example, viaconventional gate valves 219 a, 219 b (FIG. 2).

[0024] Although not shown in FIGS. 2 or 3, the transfer chamber 203 mayemploy slit valve actuators internal to the transfer chamber 203, suchas the slit valve actuator 33 of FIG. 1, to seal or open the slits 217(e.g., a conventional 45 degree-type slit valve). Alternatively, in atleast one embodiment, conventional gate valves (e.g., external gatevalve 221 (FIG. 2) that moves vertically) may be positioned outside thetransfer chamber 203 to seal and open the slits 217. Such aconfiguration may simplify the design of the domed bottom (describedbelow) of the transfer chamber 203.

[0025] Referring again to FIG. 3, the inventive transfer chamber 203 mayalso include a top member 223 which is annularly shaped, and is adaptedto be sealingly joined to an upper portion of the main body 207 via afirst O-ring 225. The inventive transfer chamber 203 may also include alid 227 which is provided to sealingly close an aperture 229 of the topmember 223 via a second O-ring 231. Other sealing mechanisms may beemployed as may other configurations for sealing the top of the transferchamber 203.

[0026] In accordance with the invention, the transfer chamber 203 alsoincludes a bottom member 233 which has a domed configuration, as bestseen in FIG. 2. As will be observed from FIG. 2, the bottom member 233has a concave configuration such that a vertical distance between thelid 227 of the transfer chamber 203 and a central portion of the bottommember 233 is greater than a vertical distance between the lid 227 andan outer edge of the bottom member 233. In one embodiment of theinvention, the bottom member 233 may be machined from a single piece ofmaterial such as stainless steel. Other materials and/or configurationsmay be used. Techniques that may be employed to manufacture the bottommember 233 are disclosed, for example, in co-pending U.S. patentapplication Ser. No. 09/523,366, filed Mar. 10, 2000 and entitled“Vacuum Processing System for Producing Components” (Attorney Docket No.2801), which is incorporated herein by reference in its entirety. Suchtechniques may include, for example, spinning, rolling and/or the like.

[0027] In one embodiment, the bottom member 233 may have a thickness ofabout 0.5 to 0.625 inches (e.g., in the domed region), as compared to athickness of three inches for conventional bottom members having a flatconfiguration and of comparable size (e.g., with an outer diameter ofabout 2.6 meters). Other thicknesses may be employed.

[0028] Referring again to FIG. 3, the bottom member 233 is adapted tocouple to and seal a bottom portion of the main body 207 via an outeredge 235 of the bottom member 233 and a third O-ring 237. The bottommember 233 has a generally circular central aperture 239. The outer edge235 and central aperture 239 may be thicker than the remainder of thebottom member 233 (e.g., about two inches square in the above describedembodiment) and may be separately formed and attached to the domedregion (e.g., via welding). Various openings and/or surface features 241may be provided to accommodate sensors, vacuum ports, gas ports, etc. Anannular plug member 243 is provided to seal the central aperture 239 ofthe bottom member 233 via a fourth O-ring 245. The plug member 243 has acentral aperture 247 sized to sealingly accommodate a portion of thesubstrate handling robot 205 (FIG. 2) which extends through the centralaperture 247 of the plug member 243 and through the central aperture 239of the bottom member 233. A fifth O-ring 249 (FIG. 3) seals the centralaperture 247 of the plug member 243 around the robot 205. Other sealingmechanisms may be employed in place of or in addition to the O-rings237, 245 and 249.

[0029] The present invention provides for a transfer chamber in whichthe bottom has a domed configuration. Consequently, for a given size oftransfer chamber, the domed bottom can be formed of thinner materialthan a conventional flat bottom. As a result, the cost and weight of thetransfer chamber bottom can be reduced. This may be particularlysignificant in the case of very large transfer chambers of the typeemployed with processing tools which process glass plates forfabrication of flat panel displays. Such a design may consume unusedspace underneath a transfer chamber and does not interfere with overheadheight limitations (e.g., due to overhead factory transport systems,ceiling heights, etc.).

[0030] As the flat panel industry continues to mature, the size of theglass plates transferred within a transfer chamber (such as the transferchamber 203) continues to grow. Current glass plate sizes are in therange of about 0.5 to 1.5 meters per side. However, larger glasssubstrates are being developed (e.g., about 2-3 meters per side).Increasing glass plate size requires transfer chambers of increasingdiameter (and larger load lock and process chambers for processing suchlarger substrates). In the near future, the flat regions of a transferchamber (e.g., flat regions 213 in FIG. 3) may reach dimensions ofgreater than about 2-4 meters to accommodate similarly sized glasssubstrates. As transfer, load lock and process chamber sizes increase,numerous factors should be considered during transfer chamber design,such as robot size, volume of the transfer chamber, space availableunderneath the transfer chamber, vacuum forces generated within thetransfer chamber, weight of the transfer chamber, cost of the transferchamber and the like.

[0031]FIG. 4 is a simplified schematic side view of an exemplaryembodiment of the transfer chamber 203 of FIGS. 2 and 3. In FIG. 4, thetransfer chamber 203 is coupled to at least one load lock chamber 401and at least one process chamber 403, and includes the main body 207 aspreviously described. For clarity, support structure for the transferchamber 203, and load lock and process chambers 401, 403, is not shownin FIG. 4.

[0032] One parameter relevant to the design of the transfer chamber 203is the space available underneath the transfer chamber 203 toaccommodate the domed bottom 233. With reference to FIG. 4, the transferchamber 203 has a minimum transfer height H_(TR) which represents theminimum height at which a substrate may be transferred within thetransfer chamber 203. The minimum transfer height H_(TR) may be anindustry standard, a requirement of the fabrication facility employingthe transfer chamber 203, or the like. In the example of FIG. 4, theminimum transfer height H_(TR) is defined relative to a floor 405 of afacility (not shown) in which the transfer chamber 203 is located. Thefloor 405 may be, for example, a floor of a clean room, a raised flooror any other lower limit on the space/area/height located below thetransfer chamber 203.

[0033] The minimum transfer height H_(TR) sets the height (H_(F)) thatthe transfer chamber 203 is positioned above the floor 405. The volumebelow the transfer chamber 203 that may be employed to accommodate thedomed bottom 233 is approximately the volume of a cylinder having adiameter equal to the inner diameter of the main body 207 of thetransfer chamber 203 (DmB) and a height equal to the height of thetransfer chamber 203 above the floor 405 (H_(F)).

[0034] As shown in FIG. 4, the domed bottom 233 of the transfer chamber203 includes a cylindrical region 233a having a height H_(D1) and adomed region 233 b having a height H_(D2). Accordingly, the volume ofthe domed bottom 233 is approximately equal to the volume of thecylindrical region 233 a plus the volume of the domed region 233 b.

[0035] It is often preferable that the transfer chamber 203 have assmall a volume as possible (e.g., to reduce pump down times therebyincreasing throughput). Because a domed configuration defines a smallervolume than a cylindrical configuration (within the same predefinedspatial region), from a volume consideration, it may be desirable tomaximize the portion of the transfer chamber 203 that is domed (e.g.,making the domed region 233 b of the domed bottom 233 larger whilereducing both the height H_(D1) of the cylindrical region 233 a of thedomed bottom 233 and the height H_(MB) of the main body 207). However,other factors influence the selection of the height H_(MB) of the mainbody 207 and the height H_(D1) of the cylindrical region 233 a of thedomed bottom 233. For example, the height H_(MB) of the main body 207 ofthe transfer chamber 203 should be sufficient to accommodate any loadlock chamber and/or process chamber coupled to the main body 207. In atleast one embodiment of the invention, the height H_(MB) of the mainbody 207 may be set, for example, based on the minimum height requiredto accommodate the slit openings 217 a, 217 b that interface with theload lock chamber 401.

[0036] With regard to the height H_(D1) of the cylindrical region 233 aof the domed bottom 233, the height H_(D1) should be sufficient toaccommodate the height of the substrate transfer robot 205 (FIG. 2). Asshown in FIG. 2, the substrate transfer robot 205 includes a first arm205 a and a second arm 205 b. When the substrate transfer robot 205 ispositioned to transfer a substrate at a height near the minimum transferheight H_(TR), such as through the opening 217 b of the main body 207 ofthe transfer chamber 203, the height H_(D1) of the cylindrical region233 a of the domed bottom 233 should be large enough to prevent thesecond arm 205 b of the robot 205 from extending into the domed region233 b of the domed bottom 233 (whether the robot 205 is in a retractedposition as shown in FIG. 2 or in an extended position such as is shownby the robot 31 of FIG. 1). If the height H_(D1) of the cylindricalregion 233 a of the domed bottom 233 is not large enough to prevent thesecond arm 205 b from extending into the domed region 233 b of the domedbottom 233, the domed region 233 b may contact and interfere withoperation of the second arm 205 b. As glass substrate size and transferchamber size increase, stiffness (and thus thickness) of each robot arm205 a, 205 b typically increases. A corresponding increase in the heightH_(D1) of the cylindrical region 233 b of the domed bottom 233 may beemployed to compensate for increased robot arm size.

[0037] Another factor that may affect the design of the transfer chamber203 is the strength required for the domed bottom 233. As transferchamber size increases, so does the force exerted on the domed bottom233 when the transfer chamber 203 is evacuated. Vacuum forces are mostpronounced at the outer edge 235 of the domed bottom 233; and the domedbottom 233 should be sufficiently strong to resist vacuum induceddeflections that may affect the ability of the domed bottom 233 to sealrelative to the main body 207 of the transfer chamber 203 and/or therobot 205 (FIG. 2).

[0038] From a strength standpoint, a spherical configuration for thedomed bottom 233 is preferred (as illustrated by domed bottom 233′ inFIG. 4). Such a configuration may be achieved by employing a radius ofcurvature (R_(D1′)) of one half of the main body 207's diameter(D_(MB)). However, as shown in FIG. 4, a spherical configuration for thedomed bottom 233 requires more space underneath the transfer chamber 203(e.g., and may interfere with the floor 405 or another space limitation)and results in a transfer chamber having a large volume. To reduce thespace/volume requirements of the domed bottom 233, a larger radius ofcurvature (R_(D1)) may be employed for a first portion 407 of the domedregion 233 a of the domed bottom 233. In at least one embodiment, theradius of curvature R_(D1) of the first portion 407 of the domed bottom233 is greater than one half of the diameter D_(MB) of the main body 207of the transfer chamber 203. In one particular embodiment, the radius ofcurvature R_(D1) is about 1.5 times the diameter D_(MB) of the main body207 of the transfer chamber 203. Other values may be employed. Selectionof the radius of curvature R_(D1) may depend on many factors such as thespace available under the transfer chamber 203, the strength of thematerial employed for the domed bottom 233, etc.

[0039] When the radius of curvature R_(D1) of the first portion 407 ofthe domed bottom 233 is greater than one half of the diameter D_(MB) ofthe main body 207 of the transfer chamber 203, the domed bottom 233 maybe provided with a second radiused portion 409 having a radius ofcurvature R_(D2). This additional radius of curvature compensates forthe mismatch between the radius of curvature R_(D1) of the first portion407 of the domed bottom 233 and the radius of the main body 207 (onehalf of D_(MB)). In at least one embodiment of the invention, the radiusof curvature R_(D2) of the second portion 409 is approximately 5-20times the thickness of the domed bottom 233 (at its thinnest point).

[0040] Based on the foregoing and in accordance with the presentinvention, the transfer chamber 203 and/or the domed bottom 233 may bedesigned as follows:

[0041] (1) determine the space underneath the transfer chamber 203available for the domed bottom 233 (e.g., based on minimum transferheight H_(TR) and/or the height H_(F) of the transfer chamber 203 aboveany interfering structure such as the floor 405);

[0042] (2) determine the radius of curvature R_(D1) for the firstportion 407 of the domed bottom 233 (e.g., based on the height H_(F) ofthe transfer chamber 203 above the floor 405, minimum transfer heightH_(TR), desired overall size of the transfer chamber 203, dimensions ofthe robot 205 such as width and height, the amount of deflection of thedomed bottom 233 that is tolerable, the vacuum levels to be employedwithin the transfer chamber 203, etc.);

[0043] (3) determine the thickness of the domed bottom 233 (e.g., basedon the radius of curvature R_(D1) for the first portion 407 of the domedbottom 233, material strength, the amount of deflection of the domedbottom 233 that is tolerable, the vacuum levels to be employed withinthe transfer chamber 203, etc.);

[0044] (4) determine the height HMB of the main body 207 of the transferchamber 203 (e.g., based on the size of the load lock and/or processchambers to be coupled to the main body 207, the height required toaccommodate the slit openings used to interface the load lock and/orprocess chambers to be coupled to the main body 207, etc.);

[0045] (5) determine the height H_(D1) of the cylindrical region 233 aof the domed bottom 233 (e.g., based on the size of the robot 205 suchas the thickness of the second arm 205 b, the minimum transfer heightH_(TR) of the transfer chamber 203, the distance between the second arm205 b and an end effector 205 c of the robot 205 (FIG. 2), etc.); and/or

[0046] (6) determine the radius of curvature R_(D2) for the secondportion 409 of the domed bottom 233 (e.g., based on the radius ofcurvature R_(D1) of the first portion 407 of the domed bottom 233, theheight H_(D1) of the cylindrical region 233 a of the domed bottom 233,etc.)

[0047] Any of the above factors may be employed alone or in combination,and in any order for designing one or more of the transfer chamber 203and/or the domed bottom 233. Other factors may be considered duringdesign of the transfer chamber 203 and/or the domed bottom 233, such asthe diameter (D_(DB)) of the aperture required to accommodate the robot205, the affect of such an aperture on domed bottom strength, or thelike.

[0048] In one exemplary embodiment of the invention, the transferchamber 203 is configured as follows:

[0049] (1) diameter D_(MB) of the main body 207 equals about 2.6 meters;

[0050] (2) height H_(MB) of the main body 207 equals about 0.8 meters;

[0051] (3) height H_(D1) of the cylindrical region 233 a of the domedbottom 233 equals about 6 inches;

[0052] (4) height H_(D2) of the domed region 233 b of the domed bottom233 equals about 12 inches;

[0053] (5) thickness of the cylindrical and domed regions 233 a, 233 bof the domed bottom 233 equals about 0.5-0.625 inches;

[0054] (6) radius of curvature R_(D1) of the radiused portion 407 of thedomed bottom 233 equals about 1.5 times the diameter of the main body207;

[0055] (7) radius of curvature R_(D2) of the radiused portion 409 of thedomed bottom 233 equals about 5-20 times the thickness of the domedregion 233 b; and

[0056] (8) thickness of the main body 207 equals about 2 inches (at itsthinnest point).

[0057] Other transfer chamber configurations may be employed.

[0058] Referring again to FIG. 2, exemplary support structure 241 forthe transfer chamber 203 and/or the robot 205 is illustrated. Suchsupport structure may include, for example, one or more suitably sizedpedestal legs 243, cross members 245 and/or braces 247. In general, anymechanism for supporting the transfer chamber 203 or the robot 205 maybe employed. The load lock chamber 15 may be supported, for example, viaa clean room wall 249 and/or the transfer chamber 205; and theprocessing chamber 17 may be supported, for example, by one or morepedestals 251 and/or cross members 253. Other supporting configurationsmay be employed.

[0059] In at least one embodiment of the invention, the supportstructure 241 is adapted to support the main body 207 of the transferchamber 203 and the robot 205 without directly supporting the domedbottom 233. For example, pedestals 243 may interface with flat regions213 (FIG. 3) of the main body 207 without contacting the domed bottom233; and cross members 245 and braces 247 may support a main trunk 255of the robot 205 without contacting the domed bottom 233 (as shown). Thedomed bottom 233 may be supported by the main body 207 (e.g., by hangingtherefrom, such as via bolts or other fastening mechanisms not shown).

[0060] In the above described embodiment, the domed bottom 233 isisolated from the support structure 241 of the main body 207 and therobot 205 (and is “floating” relative to the main body 207 and the robot205). Further in accordance with the above embodiment of the invention,a conventional bellows seal (not shown) may be employed between thedomed bottom 233 and the robot 205 to allow the domed bottom 233 to movevertically relative the robot 205 without breaking a vacuum seal formedtherebetween (e.g., via the o-rings 245, 249 in FIG. 3). In this manner,the domed bottom 233 is free to deflect during evacuation and venting ofthe transfer chamber 203, and fewer design constraints (e.g., in termsof material thickness, strength, etc.) are placed on the design of thedomed bottom 233. Further, deflections of the domed bottom 233 will notaffect the position and/or calibration of the robot 205.

[0061]FIG. 5 is a schematic vertical cross-sectional view of aprocessing tool 501 provided in accordance with an alternativeembodiment of the invention. The alternative inventive processing tool501 may be the same in all respects as the inventive processing tool 201shown in FIG. 2 except that the processing tool 501 of FIG. 4 may have atransfer chamber 503 which has a lid 527 provided in a domedconfiguration (instead of employing the flat transfer chamber lid 227shown in FIGS. 2 and 3). A transfer chamber lid having a domedconfiguration is disclosed in the above-referenced patent applicationSer. No. 09/523,366 (Attorney Docket No. 2801).

[0062] The foregoing description discloses only exemplary embodiments ofthe invention; modifications of the above disclosed apparatus which fallwithin the scope of the invention will be readily apparent to those ofordinary skill in the art. For example, although the inventive domedtransfer chamber bottom has been illustrated above as having a concaveconfiguration, the domed transfer chamber bottom may alternatively havea convex configuration (i.e., such that a vertical distance between acentral portion of the domed bottom and the lid of the transfer chamberis less than a vertical distance between an outer edge of the domedbottom and the lid of the transfer chamber). As used herein, a “domed”bottom or lid need only have a portion thereof, such as an outerportion, domed or curved. The remainder of the bottom or lid may assumeother shapes and/or may be flat. Such a domed bottom (or lid) design maybe based on one or more of transfer chamber height or width, the heightor width available underneath a transfer chamber, or the like.

[0063] It should further be recognized that if a domed lid is employed,as shown in the embodiment of FIG. 5, the configuration of the lid maybe convex (as also disclosed in the above-referenced U.S. patentapplication Ser. No. 09/523,366) rather than the concave lidconfiguration shown in FIG. 5.

[0064] Although the present invention is particularly advantageous whenapplied to a large transfer chamber of the type used in processing glassplates, the invention is also applicable to other types of processingtools, including those used to process silicon wafers. The invention isapplicable to transfer chambers adapted to couple to any number ofprocessing chambers and to any number of load lock chambers.

[0065] It should be understood that at least some of the transferchamber components illustrated in FIG. 3 can be combined with othercomponents. For example, the lid 227 and the top member 223 can becombined to form a single piece that sealingly closes the top of themain body 207 of the transfer chamber 203. Accordingly, as used in theappended claims, the term “lid” should be understood to include one, twoor more pieces which seal the top of a transfer chamber. It is alsocontemplated that components of the inventive transfer chamber shown asa single piece in FIG. 3 may be constituted by two or more pieces.

[0066] As another alternative, the bottom member 233 and the plug member243 could be combined to form a single integral piece that seals arounda substrate handling robot.

[0067] The inventive transfer chamber may be arranged to accommodate anytype of substrate handling robot, including a “frog leg” style robot.

[0068] If the bottom of the transfer chamber is employed to support theweight of the main body of the transfer chamber and/or a portion of theweight of each load lock and process chamber coupled to the transferchamber (e.g., if the domed bottom is not floating relative to the mainbody), the design of the domed bottom may be affected (e.g., the heightof the non-domed portion of the bottom, the radii of the domed portionof the bottom, material thickness, etc.).

[0069] Accordingly, while the present invention has been disclosed inconnection with exemplary embodiments thereof, it should be understoodthat other embodiments may fall within the spirit and scope of theinvention, as defined by the following claims.

The invention claimed is:
 1. A transfer chamber comprising: a main bodyhaving sidewalls adapted to couple to at least one processing chamberand at least one load lock chamber and to house at least a portion of arobot adapted to transport a substrate between the at least oneprocessing chamber and the at least one load lock chamber; a lid adaptedto couple to and to seal a top portion of the main body of the transferchamber; and a domed bottom adapted to couple to and to seal a bottomportion of the main body of the transfer chamber.
 2. The transferchamber of claim 1 wherein the main body comprises a cylindricalinterior wall and an exterior wall having a plurality of flat regionseach adapted to couple to at least one of a load lock chamber and aprocessing chamber.
 3. The transfer chamber of claim 2 wherein the mainbody is machined from a single piece of material.
 4. The transferchamber of claim 3 wherein the main body comprises aluminum.
 5. Thetransfer chamber of claim 4 wherein the sidewalls of the main body havea minimum thickness of about 2 inches.
 6. The transfer chamber of claim1 wherein the lid is substantially flat.
 7. The transfer chamber ofclaim 1 wherein the lid is domed.
 8. The transfer chamber of claim 1wherein the domed bottom is machined from a single piece of material. 9.The transfer chamber of claim 8 wherein the domed bottom comprisesstainless steel.
 10. The transfer chamber of claim 9 wherein the domedbottom has a minimum thickness of about 0.625 inches.
 11. The transferchamber of claim 1, wherein the domed bottom has a concave configurationsuch that a vertical distance between the lid and a central portion ofthe domed bottom is greater than a vertical distance between the lid andan outer edge of the domed bottom.
 12. A vacuum processing system,comprising: a transfer chamber comprising: a main body having sidewallsadapted to couple to at least one processing chamber and at least oneload lock chamber and to house at least a portion of a robot adapted totransport a substrate between the at least one processing chamber andthe at least one load lock chamber; a lid adapted to couple to and toseal a top portion of the main body of the transfer chamber; and a domedbottom adapted to couple to and to seal a bottom portion of the mainbody of the transfer chamber; at least one processing chamber coupled tothe main body of the transfer chamber; at least one load lock chambercoupled to the main body of the transfer chamber; and a robot at leastpartially extending through the domed bottom into the transfer chamber,the robot adapted to transport a substrate between the at least oneprocessing chamber and the at least one load lock chamber via thetransfer chamber.
 13. The system of claim 12 wherein the main bodycomprises a cylindrical interior wall and an exterior wall having aplurality of flat regions each adapted to couple to at least one of aload lock chamber and a processing chamber.
 14. The system of claim 13wherein the main body of the transfer chamber is machined from a singlepiece of material.
 15. The system of claim 14 wherein the main body ofthe transfer chamber comprises aluminum.
 16. The system of claim 15wherein the sidewalls of the main body of the transfer chamber have aminimum thickness of about 2 inches.
 17. The system of claim 12 whereinthe lid of the transfer chamber is substantially flat.
 18. The system ofclaim 12 wherein the lid of the transfer chamber is domed.
 19. Thesystem of claim 12 wherein the domed bottom of the transfer chamber ismachined from a single piece of material.
 20. The system of claim 19wherein the domed bottom of the transfer chamber comprises stainlesssteel.
 21. The system of claim 20 wherein the domed bottom of thetransfer chamber has a minimum thickness of about 0.625 inches.
 22. Thesystem of claim 12, wherein the domed bottom of the transfer chamber hasa concave configuration such that a vertical distance between the lid ofthe transfer chamber and a central portion of the domed bottom isgreater than a vertical distance between the lid and an outer edge ofthe domed bottom.
 23. A method of forming a domed bottom for a transferchamber adapted to couple at least one load lock chamber to at least oneprocessing chamber, the method comprising: selecting a material; andforming a domed bottom from the material, the domed bottom having anouter diameter sized to fit against and configured to form a seal with abottom portion of a main body of a transfer chamber and an aperturehaving a diameter sized to accommodate at least a portion of a robotadapted to transfer substrates between at least one load lock chamberand at least one processing chamber coupled to the transfer chamber. 24.The method of claim 23 wherein the material is stainless steel.
 25. Atransfer chamber comprising: a main body having sidewalls adapted tocouple to at least one processing chamber and at least one load lockchamber and to house at least a portion of a robot adapted to transporta substrate between the at least one processing chamber and the at leastone load lock chamber; a lid adapted to couple to and to seal a topportion of the main body of the transfer chamber; and a domed bottomadapted to couple to and to seal a bottom portion of the main body ofthe transfer chamber; wherein the domed bottom comprises: a cylindricalregion having a height adapted to accommodate at least a portion of anarm of a robot positioned within the transfer chamber; and a domedregion having: a first radiused portion having a first radius ofcurvature; and a second radiused portion extending between the firstradiused portion and the cylindrical region and having a second radiusof curvature that is less than the first radius of curvature.
 26. Thetransfer chamber of claim 25 wherein the first radius of curvature isgreater than a radius of the main body.
 27. The transfer chamber ofclaim 26 wherein the first radius of curvature is about 1.5 times adiameter of the main body.
 28. The transfer chamber of claim 25 whereinthe second radius of curvature is about 5-20 times a thickness of thedomed region.
 29. A method of forming a domed bottom for a transferchamber adapted to couple at least one load lock chamber to at least oneprocessing chamber, the method comprising: selecting a material; andforming a domed bottom from the material, the domed bottom having: acylindrical region having a height adapted to accommodate at least aportion of an arm of a robot positioned within the transfer chamber; anda domed region having: a first radiused portion having a first radius ofcurvature; and a second radiused portion extending between the firstradiused portion and the cylindrical region and having a second radiusof curvature that is less than the first radius of curvature.